African ministers are meeting European Union and US officials in the Kenyan resort Mombasa to try to revive the stalled global free trade talks.
Poor nations are angry about rich countries' farm subsidies
World Trade Organisation (WTO) talks on development collapsed in Mexico last September amid rows about rich countries' agricultural subsidies.
But the EU said it was bringing no new proposals to the meeting.
And US Trade Representative Robert Zoellick said there was "uncertainty about how to re-engage productively".
African countries will call again upon EU and US officials to open up their markets to goods grown by millions of peasant farmers.
"We've been so flexible so far and now we've reached a point
whereby if we continue to be flexible we shall be breaking our
backs," Tanzanian Trade Minister Juma Ngasongwa told Reuters news agency.